I HAVE A CONFESSION to make: For nearly a decade, I kept contraband in my freezer. It was a stash of Sichuan peppercorn, the bright and earthy Asian spice that tingles and numbs the tongue. Harvested from prickly ash shrubs and trees in temperate parts of Asia, Sichuan peppercorns had been banned from the U.S. in 1968 out of fear they might spread citrus canker.

The spice is often combined with chilies for a sensation the Chinese call ma la—literally "numbing-hot." It was a food buzz that intrigued me because it was like no other. (Despite the name, the reddish-brown pods are not related to black pepper.) The zingy husks are used in China, where the spice is called hua jiao ("flower pepper"), while Japanese cuisine favors the pod's milder berries, known as sansho. In any form, that lemony tang is unmistakable.

I got my hands on some in 1996, and since I didn't know when I'd get more, I used the peppercorns judiciously—roasting them with salt, say, to make a zesty dip for fried chicken. My favorite way to deploy them was to pound and scatter them into mapo tofu, a Sichuan classic of velvety tofu and ground meat swimming in a silky sauce. When the U.S. lifted the ban on Sichuan peppercorns in 2005, I rejoiced.

ENLARGE

Sichuan peppercorns
F. Martin Ramin for The Wall Street Journal

A few years later, while researching my "Asian Tofu" cookbook, I traveled to Chengdu, the capital of China's Sichuan province. The peppercorns were plentiful at every market I visited, often displayed alongside chilies, their ma la partner. It was a sultry September, and a snack of dan dan noodles seasoned with salty preserved vegetables, perky Sichuan peppercorns and chili oil kept me alert in the intense humidity.

One family I visited used Sichuan peppercorns in most everything they served me. To finish a stir-fry, they sprinkled on a bit of the ground spice just as if it were black or white pepper. The family's version of mapo tofu relied solely on hua jiao for seasoning. For my taste, the result had too much ma and not enough la—an object lesson in the importance of striking the right balance between chilies and peppercorns. One of their kitchen drawers held a jar of ground peppercorns moistened by oil—a brilliant idea, because the oil captured the spice's zing and kept it always at the ready. The family used this paste to season all kinds of salads and sauces.

In other encounters, Sichuan peppercorns played a less obvious role. One restaurant served its signature duck with a fragrant chili mixture that contained just a hint of the spice's citrusy brightness and numbing edge. A locally made candy had a suggestion of it too. I was inspired to experiment in countless new ways—all the more so because nowadays, Sichuan peppercorns are readily obtained Stateside, not only in Chinese markets but online, at sources like kalustyans.com. I've even seen them at Whole Foods. Looking back at my years on the wrong side of the law, it seems almost too easy.

Mapo Tofu (Spicy Tofu With Beef and Sichuan Peppercorn)

You can find Chinese chili bean sauce at Asian markets. The label will read dou ban jiang or toban djan; the word Pixian signals an excellent version made in Sichuan.

Total Time: 30 minutes Serves: 4

Ingredients

16 ounces medium-firm tofu, cut into ½-inch cubes

1 teaspoon Sichuan peppercorn

3 tablespoons canola oil

6 ounces ground beef or pork, roughly chopped

1 teaspoon minced fresh ginger

1½ teaspoons chili flakes

1 tablespoon fermented black beans, optional

2½ to 3 tablespoons Chinese chili bean sauce

1 generous teaspoon sugar

2 teaspoons soy sauce

1 1/3 cups boiling water

Salt, to taste

2 large scallions, cut on the diagonal into 1½-inch pieces

1½ tablespoons cornstarch dissolved in 3 tablespoons water

What To Do

1. Put tofu in a heatproof bowl. Bring a kettle of water to a rolling boil. Remove water from heat, then pour over tofu to cover. Let sit 15 minutes.

2. Meanwhile, in a large wok or skillet, toast peppercorns over medium heat until fragrant and slightly darkened, 2-3 minutes. Let cool briefly, then pound with a mortar and pestle or grind in a coffee or spice grinder. Set aside. Drain tofu and set near stove.

3. Heat oil in wok or skillet over high heat. Add beef, using a wooden spoon to crumble into small pieces. Stir-fry until cooked through, about 2 minutes. Add ginger, chili flakes, fermented black beans (if using) and chili sauce. Cook, stirring constantly, until beef is a rich reddish-brown color and oil is slightly red, about 2 minutes. Add sugar and soy sauce, stir to combine, then add tofu. Gently stir or shake wok to combine without breaking up tofu.

4. Pour in boiling water. Bring to a vigorous simmer, and cook to allow tofu to absorb flavors, about 3 minutes. Season with salt or sugar to taste.

5. Add scallions and stir to combine. Pour enough dissolved cornstarch into wok to thicken sauce. (You may not need to use it all.) Add reserved ground peppercorn, stir once more and transfer to a shallow bowl or divide among four serving dishes. Serve immediately with hot rice.

What To Do

2. Heat oil in a wok or skillet over medium heat. Add chilies and peppercorns and stir-fry until fragrant, 15 seconds. Add meat and ya cai, using a wooden spoon to crumble meat. Add remaining soy sauce and stir-fry until meat is cooked through, about 2 minutes. Set aside.

3. Cook noodles as directed on package. Drain under warm running water to remove excess starch. Divide hot noodles among bowls with sauce. Top with meat and scallions. Invite guests to mix before eating.

Chili-Sichuan Peppercorn Mix

Use this to dip or garnish poached chicken, fried tofu or steamed vegetables. You can find Sichuan peppercorn and other ingredients at Asian markets or at online sources such as ethnicfoodsco.com.

Total Time: 5 minutes Makes: 1/3 cup

Ingredients

3 tablespoons gochu garu (Korean red pepper powder)

1 teaspoon Sichuan peppercorn, toasted and ground

¾ teaspoon toasted white sesame seeds

½ teaspoon sea salt

2 tablespoons canola or peanut oil

½ teaspoon sugar

What To Do

1. In a small bowl, combine Korean red pepper powder, Sichuan peppercorn, sesame seeds and salt. Put the oil in a small saucepan or skillet and heat over medium-high heat until just smoking.

3. Let cool a few minutes, taste and adjust the flavor with extra salt or sugar. The mixture is ready to use. Or, keep in an airtight container at room temperature for up to 2 days or refrigerate for up to a week.

—Adapted from "Asian Tofu"

Sichuan Peppercorn Paste

This paste preserves the peppercorns' zing and will keep at room temperature for a month.

Total Time: 10 minutes Makes: 1½ tablespoons

3 tablespoons Sichuan peppercorn

1 tablespoon canola oil

In batches, use a clean spice or coffee grinder to reduce peppercorns to a sawdust-like texture. Transfer to a small jar. Stir in oil to moisten. Let sit for 5 minutes before using.

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